1. Field of the Invention
The present invention relates to a vehicle height adjustment device suitably used in a motorcycle and the like.
2. Description of the Related Art
A vehicle height of motorcycles is preferably low upon stop of the motorcycle, so as to enable a short rider to easily stand with his/her feet on the ground, without tumbling. On the other hand, a certain degree of vehicle height is needed in terms of bank angle, shock absorption and the like during travel. In some American-model motorcycles and the like, moreover, a low vehicle height upon stop is also required from the viewpoint of exterior design.
Accordingly, conventional vehicle height adjustment devices for vehicles have been proposed, such as the one in Japanese Examined Patent Publication No. H8-22680. That vehicle height adjustment device has a damper tube provided in either a vehicle body side or an axle side; a piston rod, provided in the other from among the vehicle body side and the axle side, and that extends and retracts with respect to the damper tube by sliding in an oil chamber within the damper tube; a hydraulic jack that is provided in either the damper tube or the piston rod; a spring receiver that is supported on a plunger that is inserted in a jack chamber of the hydraulic jack; a suspension spring that is interposed between the spring receiver and a spring receiver that is provided in the other from among the damper tube and the piston rod; a hydraulic pump that supplies a working oil to the jack chamber of the hydraulic jack through a pumping operation resulting from extension and retraction of the piston rod with respect to the damper tube; and a switching valve that closes so as to stop the working oil that is supplied to the jack chamber of the hydraulic jack, or that opens so as to discharge the working oil; such that the vehicle height can be adjusted through extension and retraction of the piston rod with respect to the damper tube.
In the vehicle height adjustment device of vehicles disclosed in Japanese Examined Patent Publication No. H8-22680, vehicle height is lowered automatically at or below a set vehicle speed and is automatically raised when the set vehicle speed is exceeded.    Patent document: Japanese Examined Patent Publication No. H8-22680